The Airborne Kingdom roams the skies, a vast, rattling amoeba of propellers and minarets, hissing forges and thundering gears. It has to keep moving because it has to keep eating. As it coasts between clouds, painted planes slide from curving hangar bays, falling like windblown embers toward patches of coal and timber. The landscape is swiftly exhausted, though many of the key resources regrow almost as fast. Lakes are drained in hours, hillsides sucked clean of ore, forests hacked to stubble before they've even cleared the Kingdom's shadow.
Occasionally, during its grazing, the Kingdom uncovers a town, a tiny toe-nail clipping of huts and cooking fires, poking from the dusty mosaic tiles and cracked flagstones of the map. It sends emissaries to gather up the people of the earth and transform them into creatures of the air. Some surface-dwellers are easily won over by tales over high adventure. Others are resistant, put off by hints of dissatisfaction in the streets above. No matter. The Kingdom will be back for them, once its existing residents are happier.
A little less often, the Kingdom comes across another kingdom - a towering sandstone palace or a jaunty stack of windmills, its name embossed on the ground nearby. When it encounters such places it descends in greater earnest, blotting out the sun and filling the ears of the locals with its Prophecy - the legend of the Airborne Kingdom as unifier of humanity, stepping stone to heaven. While not always receptive to these promises of a golden tomorrow, the surface kingdoms are willing to pledge loyalty in return for a couple of favours, typically of the "fetch this" and "supply X of Y" variety. One asks the Airborne Kingdom to track down a special breed of tree to repopulate a sacred grove. Another asks it to carry three scholars to neighbouring cities. Others simply need wood and cloth to build new homes.
